b9e1d14460
The 'Apply the retpoline transformation to indirect jumps in the raw ASM' commit in 6.4 added an instruction to the sigcode. This fixes the offset to look for sigreturn and mantains backward compat. maintainer timeout
108 lines
3.5 KiB
Plaintext
108 lines
3.5 KiB
Plaintext
$OpenBSD: patch-gdb_amd64obsd-tdep_c,v 1.3 2020/06/01 21:44:49 kurt Exp $
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Index: gdb/amd64obsd-tdep.c
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--- gdb/amd64obsd-tdep.c.orig
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+++ gdb/amd64obsd-tdep.c
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@@ -76,8 +76,40 @@ amd64obsd_iterate_over_regset_sections (struct gdbarch
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/* Support for signal handlers. */
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/* Default page size. */
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-static const int amd64obsd_page_size = 4096;
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+static const CORE_ADDR amd64obsd_page_size = 4096;
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+/* Offset & instructions for sigreturn(2). */
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+
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+#define SIGRETURN_INSN_LEN 9
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+
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+struct amd64obsd_sigreturn_info_t {
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+ int offset;
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+ gdb_byte sigreturn[SIGRETURN_INSN_LEN];
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+};
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+
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+static const amd64obsd_sigreturn_info_t
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+ amd64obsd_sigreturn_info[] = {
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+ /* OpenBSD 6.4 */
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+ { 9, { 0x48, 0xc7, 0xc0,
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+ 0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */
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+ 0x0f, 0x05 } }, /* syscall */
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+ /* OpenBSD 5.1 */
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+ { 6, { 0x48, 0xc7, 0xc0,
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+ 0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */
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+ 0x0f, 0x05 } }, /* syscall */
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+ { 7, { 0x48, 0xc7, 0xc0,
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+ 0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */
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+ 0x0f, 0x05 } }, /* syscall */
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+ /* OpenBSD 5.0 */
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+ { 6, { 0x48, 0xc7, 0xc0,
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+ 0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */
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+ 0xcd, 0x80 } }, /* int $0x80 */
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+ { 7, { 0x48, 0xc7, 0xc0,
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+ 0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */
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+ 0xcd, 0x80 } }, /* int $0x80 */
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+ { -1, {} }
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+};
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+
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/* Return whether THIS_FRAME corresponds to an OpenBSD sigtramp
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routine. */
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@@ -86,20 +118,8 @@ amd64obsd_sigtramp_p (struct frame_info *this_frame)
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{
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CORE_ADDR pc = get_frame_pc (this_frame);
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CORE_ADDR start_pc = (pc & ~(amd64obsd_page_size - 1));
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- const gdb_byte osigreturn[] =
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- {
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- 0x48, 0xc7, 0xc0,
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- 0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */
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- 0xcd, 0x80 /* int $0x80 */
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- };
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- const gdb_byte sigreturn[] =
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- {
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- 0x48, 0xc7, 0xc0,
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- 0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */
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- 0x0f, 0x05 /* syscall */
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- };
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- size_t buflen = (sizeof sigreturn) + 1;
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- gdb_byte *buf;
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+ const amd64obsd_sigreturn_info_t *info;
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+ gdb_byte buf[SIGRETURN_INSN_LEN];
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const char *name;
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/* If the function has a valid symbol name, it isn't a
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@@ -113,22 +133,22 @@ amd64obsd_sigtramp_p (struct frame_info *this_frame)
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if (find_pc_section (pc) != NULL)
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return 0;
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- /* If we can't read the instructions at START_PC, return zero. */
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- buf = (gdb_byte *) alloca ((sizeof sigreturn) + 1);
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- if (!safe_frame_unwind_memory (this_frame, start_pc + 6, buf, buflen))
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- return 0;
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+ for (info = amd64obsd_sigreturn_info; info->offset != -1; info++)
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+ {
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- /* Check for sigreturn(2). Depending on how the assembler encoded
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- the `movq %rsp, %rdi' instruction, the code starts at offset 6 or
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- 7. OpenBSD 5.0 and later use the `syscall' instruction. Older
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- versions use `int $0x80'. Check for both. */
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- if (memcmp (buf, sigreturn, sizeof sigreturn)
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- && memcmp (buf + 1, sigreturn, sizeof sigreturn)
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- && memcmp (buf, osigreturn, sizeof osigreturn)
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- && memcmp (buf + 1, osigreturn, sizeof osigreturn))
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- return 0;
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+ /* If we can't read the instructions at return zero. */
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+ if (!safe_frame_unwind_memory (this_frame,
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+ start_pc + info->offset, buf, sizeof buf))
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+ continue;
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- return 1;
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+ /* Check for sigreturn(2). */
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+ if (memcmp (buf, info->sigreturn, sizeof buf))
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+ continue;
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+
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+ return 1;
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+ }
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+
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+ return 0;
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}
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/* Assuming THIS_FRAME is for a BSD sigtramp routine, return the
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